Darwin-Hooker Letters : Letter from C. R. Darwin to J. D. Hooker 19 July [1856]
Darwin, Charles Robert
Darwin-Hooker Letters
<p style='text-align: justify;'>Multiple creations.</p><p style='text-align: justify;'>Necessity for crossing in plants and animals: JDH to take up the subject; explains separate sexes in trees.</p><p style='text-align: justify;'>Continental extensions.</p>